With the development of the network, information grows in an explosive way, and people's data reaches an unprecedented scale. The storage and management of the large-scale data becomes a big challenge. Although the capacity of a hard disk is increasingly large and a storage speed is continuously increased, it is difficult to satisfy requirements of mass information management in aspects such as extensibility, reliability, and high availability of a storage sub-system in conventional ways of direct hard disk storage and adopting a plurality of external disk arrays.
In the prior art, a typical block storage system may generally be simplified into an origination end and a destination end. The origination end locally generates a volume and establishes a connection with the destination end, and meanwhile forwards an input (Input; I for short)/output (Output; O for short) request for a local device file to the destination end for processing. The destination end manages a storage device and process a final I/O request. The origination end and the destination end communicate with each other through a block interface of a storage protocol such as an internet small computer system interface (internet Small Computer System Interface; iSCSI for short)/fiber channel (Fiber Channel; FC for short)/advanced technology attachment over Ethernet (Advanced Technology Attachment over Ethernet; AOE for short)/network block device (Network Block Device; NBD for short).
The origination end mainly includes an access unit, for implementing local volume management and establishing a connection with the destination end through protocols (such as the iSCSI, the FC, or the AOE) and communicating with the destination end. The destination end mainly includes a volume control unit and a redundant array of independent disk (Redundant Array of Independent Disk; RAID for short) control unit. The RAID control unit manages a specific physical disk, builds an RAID group, and forms a logical disk. The volume control unit manages the logical disk generated by the RAID control unit, divides logical volumes according to requirements, and exposes the logical volumes through the protocol such as the iSCSI, the FC, or the AOE for the origination end to use.
However, in the prior art, a block storage service provided by the destination end has a limit in aspects such as reliability, availability, extensibility, and cheapness.
Specifically, in the aspects of reliability and availability, in the prior art, data reliability is ensured mainly by building the RAID in a cabinet of the destination end and adopting multi-controller head redundancy (for example, a dual controller disk array), but if a power supply of the cabinet is faulty or two or more controller heads are faulty at the same time, problems such as data loss or service interruption may occur, further affecting the availability. In the aspect of extensibility, if the destination end adopts the Internet storage area network (Internet Storage Area Network; IP SAN for short) or fiber channel storage area network (FC Storage Area Network; FC SAN for short), the capacity of the destination end is limited by the processing capability of the controller head of the IP SAN or the FC SAN, so that the maximum supported capacity is limited, and a large scale expansion cannot be performed.
In the aspect of maintainability, in a disk array built by the RAID group, when a disk in the RAID group is faulty, the disk needs to be replaced in time and the RAID needs to be rebuilt, to ensure redundancy and data reliability. This requires the maintenance personnel to perform the replacement at any time, and the system cannot process such fault automatically.
In the aspect of cheapness, the price of the IP SAN or the FC SAN, especially the FC SAN, used as the destination end is high, and relevant switch devices required to support the IP SAN or the FC SAN are also expensive. A storage server used as the destination end is relatively cheap, but the storage server has a low requirement on a processor and a memory, so the disk I/O performance is low.